Air and gas mixing device.



C. Rv POMAVILLE.

AIR AND GAS MIXING DEVICE.

APPLICATION FILED MAR. 4| 1915.

Patented June 29, 1915.

CEPHRES R. PO'HAVILLE, OF DETIfOIT, MICHIGAN, ASSIGNOR TO THE MICHIGANSTOVE COMPANY, QF'DETROIT, MICHIGAN, A CORPORATION OF MICHIGAN.

AIR AND GAS MIXING DEVICE.

Specification of Letters Patent.

Patented June 29, 1915.

To all whom it may concern Be it known that I, CEPHREs R. POMA- VILLE, acitizen of the United States of America, residing at Detroit, in thecounty of Wayne and State of Michigan, have invented certain new anduseful Improvements in Air and Gas Mixing Devices, .of Which thefollowing is a specification, reference being had therein to theaccompanying drawings.

The ovens of gas ranges are enteredby an oven door and, are heated bygas burners; Such burners have orifices supplying an explosive mixtureof gas and air which is ignited at the orifice. If too much or toolittle air is mixed with the gas the mixture will not ignite or if suchmixture is changed while the gas is burning, the flames will beextinguished. The mixture of gas and air is intended to be at the end ofthe burner farthest from the flame orifices and consists of a gas jetdischarging toward the burning end and to provide for the correct amountof air, openings are provided for its admission; the force of the gasjetinducin a current sufficient to draw in the air which is mixed as thegas and air rush through the pipe leading to the flame orifices. As theinduced current is changed by variations in gas pressure, adjustableshutters are pro vided to vary the air mixture until the flame showsproper combustion and until the oven heats properly. Even the propermixture of gas and air will not burn at the orifices without a secondarysupply of air. There is therefore an opening one or more) to supply suchair at the point of combustion. In some ovens the openings are quitelarge in others quite small.

v By opening the oven door quickly a suction is produced which causes asudden rapid flow of'secondary air through the openings providedtherefor, and also causes a suction on the burner itself, which pulls inan extra amount of air. If the gas is on fullyand the air isproportioned properly, the forceinside the tube is more than that causedby the oven door opening and will therefore not be influenced. Closingthe oven door with a bang produces the con trary effect. The airshutters are set for the maximum gas at full flame and when the flame isturned very low the induced current is very weak and draws in only asmuch air as is needed but the air mixer openings are still open. Now ifthe oven door is opened very suddenly, the secondary air/openings cannotsupply enough to meet the suction, which causes such a strong pull onthe flame orifices, with their-very small flames, that an extra quantityof air is drawn in at the open mixer and this excess air extinguishesthe flames. hen the door is closed very quickly an air pressure iscaused in the oven, which extra air cannot go fast enough out of thesecondary air openings and therefore is pressed into the flame orificesextinguishing the flames. The user in either case may not notice thatthere is no flame and as the gas is still on an. explosion will shortlyoccur when the gas reaches a flame in some other part'of the stove. Theobject of this-invention s to open or close the air mixer as the gas isdecreased or increased. Thus when the flame is very low the air openingis very nearly closed and when the oven door is opened or closed, thesecondary air openings are obliged to take care of the suction orincreased air pressure in the oven and cannot pull extra air through theair mixers or push air into the flame orifices. The flame cannot beextinguished however low it is turned. Another object of this inventionis to provide a device wherein the means for controlling the passage ofair and the means for controlling the passage of gas to the device aresimultaneously operated by a common operating element, and said meansare so correlated that when a given quantity of gas passes through thedevice a given quantity of air will also pass therethrough and as thequalntity of air is increased or decreased the quantity of gas will beproportionately increased or decreased.

A further object of this invention is to provide an air and gas mixingdevice embodying a gas inlet valve having a plug, means movable with theplug of the valve for regulating the admixture of air and gas, and meansforming part of the first mentioned means adapted to independentlyproportion the quantity of air for mixing purposes.

Apreferrecl form of air and as mixing device will be hereinafterspecifically described and then claimed, and reference will now be hadto the drawing, wherein- Figure 1 is a front elevation of a portion of agas-range, partly broken away and partly in section, illustrating an airand gas mixing device in connection with the burner of a gas heatedoven; Fig. 2 is a side elevation of an air and gas mixing device inaccordance with this invention; Fig. 3 is an end view of the sameshowing the gas and air wide open and the regulating shutter halfclosed; Fig. 4 is a plan of thedevice; Fig. 5 is a longitudinalsectional view illustrating the shutter construction; Fig. 6 is a detailsectional view of a portion of the shutter, and Figs. 7 to 10 inclusiveare diagrammatic views illustrating the relative positions of shuttersand a valve plug.

In the drawings, 1 denotes an ordinary gas burner pipe having a bellshaped end 2 providing a mixing chamber 3. The bell shaped end of thepipe has diametrically upposed inwardly projecting lugs 4. Connected tosaid lugs by screws 5 or other fastening means is a stationary end plate6 provided with a concentric opening 7 and a plurality of equally spacedsector shaped openings 8, the latter admitting air to the chamber 3. Theperipheral edge of the end plates 6 protrudes from the bell shaped endof the burner pipe and constitutes a guide for an outerrotary shutter 9and an inner rotary shutter 10. The inner rotary shutter 10 has aconcentric opening 11 registering with the opening 7 of the end plateand openings 12 corresponding in size and shape to the openings 8 of theend plate and adapted to register therewith.

The outer rotary shutter 9 has a concentric opening formed by a sleeve13 which extends into the openings 11 and 7 and centers the outershutter relative to the inner shutter and the end plate. The outershutter 9 has openings 14: corresponding in size and shape to theopenings 12 of the inner shutter-10 and the peripheral edges of theouter shutter terminate in an annular flange 15 surrounding theperipheraledges of the end plate 6 and the inner shutter 10. Thisperipheral flange has a plurality of prongs or teats 16 which are bentinwardly to movably hold the outer and inner shutters on the end plate6.

The flange 15 of the outer shutter 9 is cut away, as at 1'7, and theperipheral edge of the inner shutter 10 is provided with an aperturedlug 18 which is bent into the plane of the outer shutter 9, as bestshown in Fig. 6. The cut away portion 17 of'the flange providesclearance for the .pertured lug 18, and connected to said lug y a screw19 or other fastening means is a washer or retaining member 20 havingthe edge thereof overlying the. outer shutter 9, to frictionally holdthe inner shutter in an adjusted position relative to'the outer shutter.An adjustment of the inner shutter relative to the outer shutter isaccomplished by holding the outer shutter and using the lug 18 as afinger piece for shifting the inner shutter; the re taining member '20sliding over the outer shutter within the space defined by the cut awayportion 17 of the flange 15. This cut away portion of the flange is ofsufficient length to allow the inner and outer shutters to be adjustedwhereby they will cooperate in providing air inlet openings, the area ofwhich can be increased or decreased.

Extending through the sleeve 13 of the outer shutter is a nozzle 21 of agas inlet valve or cock22, said valve being in communication with asuitable supply of gas. The gas inlet valve is of the conventional formwith the exception of the plug 23 of said valve, said plughaving an endthereof provided with a rigid arm 24 radially disposed relative to theplug body. The outer end of the arm-24 terminates in a knob orprotuberance 25 between the side walls 26 of a channel member 27 securedto the outer shutter 9, contiguous to the flange 15 thereof. Wheninstalling an air and gas mixing device in accordance with thisinvention, the inner and outer shutters 10 and 9 are adjusted wherebythe openings 12 and 1 1 thereof completely register. The inner and outershutters. as a unitary structure are shifted whereby the openingsthereof will fully register with the openings 8 of the end plate 6 whenthe gas is turned on full. Holding the outer shutter 9, the innershutter 10 is now adjusted, if necessary, to decrease the area of theair inlet openings until there is a'proper admixture of air and gas tomaintain a perfect combustion at aburner 28 in communication with thepipe 1. Adjustment of the shutters as a unitary structure relative tothe end plate 6 is somewhat similar to adjusting or setting an ordinaryair mixture until there is a fair commingling of air and gas, which canbe determined by observing the flame. at the burner 28. Now, with theinner and outer shutters properly adjusted they are shifted as a unit insynchronism with the movement of the valve plug 23, and as the rotaryshutter is moved, it regulates the admission of air to the mixingchamber 3, the quantity 0% air being in proportion to the quantity 0gas.

As further illustrating the action of thegas cock relative to the aircontrol, reference will be had to Figs. 7 to '10 inclusive, showing thegas cock plug and the air control in the same plane, while in actualarrangement, they are disposed in planes at right angles. When the plugis turned wide open, as in Fig. 7, all of the openings of the aircontrol are'wide open, and when the plug is turned a sixteenth of arevolution, as in Fig. 8, the gas is cut down one-half and the airopenings are half opened. When the plug is turned an eighth of arevolution, as in Fig. 9, the air openings are closed. Just as the gasopening of the cock plug is closed or opened, the air openings areclosed. The plug will not hold gas in this position. When the cock plugis turned a quarter of a revolution or 45 degrees, as in Fig. 10, thegas is securely out ofi' and the air openings are wide open. This iscaused by it taking a 45 degree turn ,to close, the air openings. Theopenings forthe gas in the plug 23 and for the air in the end plate 6each extend for forty-five degrees. There are four openings provided forthe air'and two openings for the gas, which gives four open positions ofthe air valve and two 'open positions of the gas valve for a completerevolution of each valve and with the valves restricted to a;

halfturn by the construction shown, there are one open position of thegas valve and two open positions of the air valve.

Fig. 1 illustrates the use of the air and gas mixing device, more thanone, in connectionwith a stove having a gas heated oven 29 heated by thegas burner 28. It will be observed that the bottom of the oven has anair inlet opening 30, which together with openings in the rear wall ofthe oven sustains combustion in the oven when the door 31 thereof isclosed.

When the gasis just opened and. therefore I avery low flame, or turneddown very low,

nearly turned ofi; the air openings are closed, and enough air-leaks tosupply combustion. Now ifthe oven shut or opened suddenly there isenoughin the burner to prevent pressure t e comof which there may bedoor is banged pressed air inthe oven from overcoming it and forcing theflame back int'othe burner; or a suction in the oven when the door isopened suddenly from drawingair'quickly enoughthrough the leakageopenings of the change the mixture of gas and having air inlet openings,of shutters movable on said mixing chamber and having air inlet openingsadapted to register with the openings of said mixing adjustablyholding)said shutters relative to 'each other where y said shutters can be movedas a unit, a gas valveadapted to ad mit gas to'said mixm chamber, and aeonnection between one o said shutters andthe plug of said valve adaptedto adjust said shutters as a unit simultaneously with an' adjustment ofsaid valve.

In testimony whereof I,aflix my signature in presenceof two witnesses.CEPHRES R. POMAVILLE.

Witne:-

WILLIAM J K EP,- Q KARL H. BUTLER.

chamber, means

